In one known method of manufacturing a fibre reinforced metal matrix composite article, as disclosed in European patent No. EP0831154B1, a plurality of metal-coated fibres are placed in an annular groove in a metal ring and a further metal ring is placed on top of the metal-coated fibres. Each of the metal-coated fibres is wound spirally in a plane and the metal-coated fibre spirals are stacked in the annular groove in the metal ring. The metal rings are pressed predominantly axially to consolidate the assembly and to diffusion bond the metal rings and the metal coated fibre spirals together to form an integral structure.
In a further known method of manufacturing a fibre reinforced metal matrix composite article, as disclosed in European patent application No. EP1288324A2, the arrangement described in EP0831154B1 is modified by the inclusion of metal wires in the annular groove in the metal ring with the metal-coated fibres. Each of the metal wires is wound spirally in a plane and the metal wire spirals are stacked in the annular groove in the metal ring with the metal-coated fibre spirals.
In these methods of manufacturing a fibre reinforced metal matrix composite the metal coated fibres, or the metal coated fibres and metal wires, are wound spirally in a plane on a former and the metal coated fibre spirals, or metal coated fibre spirals and metal wire spirals, are temporarily held together with a glue to enable the metal coated fibre spirals, or metal coated fibre spirals and metal wire spirals, to be assembled in the annular groove in the metal ring. The glue is applied locally to the metal-coated fibre spirals, or metal coated fibre spirals and metal wire spirals.
Due to necessary clearances and slight variation in the diameter of the fibres or fibres and wires, the metal coated fibre spirals, or metal coated fibre spirals and metal wire spirals are not perfectly flat, i.e. adjacent metal coated fibres, or metal coated fibres and metal wires, are slightly out of plane. As a result the spirals are not ideally packed during the dry assembly of the spirals in the annular groove in the metal ring and this leaves undesirable excess free space between the metal-coated fibres. The excess free space means that the confronting faces of the metal rings will not abut each other and it is not possible to seal the assembly. It is then necessary to provide a deeper annular groove in the metal ring in order to allow the confronting faces of the metal rings to abut each other. An increase in the depth of the annular groove is undesirable because the further metal ring has to be moved a greater distance to achieve consolidation. Additionally, the excess free space allows the metal coated fibres to move out of position and may even allow some of the metal coated fibres to cross other metal coated fibres and this may results in breaking of the metal coated fibres during processing, essentially creating material defects.